Antibiotic impregnated bioabsorbable carriers for treatment of chronic intramedullary osteomyelitis

Abstract

The treatment of chronic osteomyelitis involves a debridement of affected non-viable tissue and the use of antibiotics. Where surgery leaves a cavity, dead space management is practised with antibiotic impregnated cement. These depots of local antibiotics are variable in elution properties and need removal. We review the use of bioabsorbable synthetic calcium sulphate as a carrier of gentamicin and as an adjunct in treating intramedullary osteomyelitis. A retrospective review of cases treated consecutively from 2006 to 2010 in the Royal Liverpool University Hospital was undertaken. Variables recorded included aetiology, previous interventions, diagnostic criteria, radiological features, serology and microbiology. The Cierney-Mader system was used to classify. Treatment involved removal of implants (if any), intramedullary debridement and local resection (if needed), lavage and instillation of the gentamicin carrier, supplemented with systemic antibiotics. Follow-up involved a survival analysis to time to recurrence, clinical and functional assessment (AOFAS-Ankle/IOWA knee/Oxford Hip) and general health outcome (SF36). There were 31 patients (22 male, 9 female). The mean age was 47 years (20-67). Twenty-five cases were post-surgery (6 open fractures) and 6 were haematogenous in origin. The median duration of osteomyelitis was 1.6yrs. The bones affected were 42% femur, 45% tibia, 3% radius and 10% humerus. 11 cases had diffuse as well as intramedullary involvement. 9 cases underwent segment resection and bone transport. We identified Staphylococcus Aureus in 16 and Coagulase Negative Staphylococcus in 6 cases. The median follow-up was 1.7 years (0.5-5.6). The median scores attained were: AOFAS-78, DASH-32, IOWA-71, Oxford-32. There were two recurrences. Dead space management of intramedullary infections is difficult. We describe a method for delivery of local antibiotics and provide early evidence to its efficacy. The treatment success to date is 93%. Bioabsorbable carriers of antibiotics are efficacious adjuncts to surgical treatment of intramedullary osteomyelitis.